Medicaments may be delivered to patients by a variety of ways including oral, intravenous, intramuscular, inhalation, topical, rectal, subcutaneous or local routes of administration to treat the target site. The method of delivery chosen depends, among other things, upon the condition being treated, desired therapeutic concentration of the medicament and the duration of medicament concentration that must be maintained at the target site.
Recently, there has been considerable interest in delivering medicaments via the oral cavity (e.g., gums, buccal, and sublingual areas, etc.). Delivery to target sites of the oral cavity has several advantages. One advantage is that it allows localized treatment of the teeth, gums and other soft tissues. Another advantage is that the oral cavity has an extensive network of blood capillaries under the mucosa that is particularly suited to provide rapid and effective systemic absorption of systemic medicaments.
Delivery of medicaments to target sites in the oral cavity, unlike the intravenous (IV), intramuscular (IM), and subcutaneous (SC) routes, does not require sterilized hypodermic needles and does not raise concerns about the safe disposal of needles and accidental needle sticks.
Many, if not most, patients experience anxiety and exhibit symptoms of stress when faced with hypodermic injections via the IM, IV, or SC routes. Burning, edema, swelling, turgidity, hardness and soreness at the injection site can often occur.
Non-invasive delivery of medicaments to the oral cavity avoids these problems associated with injections. Non-invasive delivery of medicaments to the oral cavity also has the advantage of avoiding hepatic first pass metabolism, where enzymatic degradation within the gastrointestinal tract destroys certain medicaments. For example, therapeutic peptides such as insulin, erythropoietin, and human growth hormone do not survive the acidic milieu of the stomach and cannot be administered orally.
Many oral medicaments are commercially available for cosmetic and therapeutic use, which are delivered locally to the oral cavity. These medicaments are formulated as mouthwashes, rinses, toothpastes, dental gels, tooth powder, chewing gum, lozenges, strips and similar products to treat a variety of conditions including preventing dental calculus formation, dental caries, periodontitis and gingivitis, tooth whitening, as well as the elimination of halitosis. While these formulations provide some benefits, they often require a higher dose and do not stay at the target site long enough for adequate delivery of the medicament and are diluted away by saliva also decreasing effectiveness.
Oral appliances that allow non-invasive delivery of medicaments have been developed that have a reservoir to hold liquid medicaments to be delivered. These oral appliances can be universal sizes to generically fit adults or custom made for a precise fit to the teeth and gums of the individual patient. To whiten teeth, these oral appliances are becoming increasingly popular as over-the-counter tooth whitening systems or as part of a treatment plan from dental professionals.
Many oral appliances require the patient or dental professional to fill the reservoir with the liquid medicament. This can be costly and time consuming, and can be very messy with bulky dispensers requiring dexterity particularly when the patient is filling the oral appliance by himself/herself in the confines of their home. This leads to poor patient compliance and the failure of the treatment itself. Often the liquid medicament held by the oral appliance undesirably leaks out of the oral appliance and contacts off target areas of the mouth causing unwanted treatment of these non-targeted areas often with deleterious side effects such as burning, stinging and irritation and altered taste sensations. Sometimes medicament can leak out of the appliance and the patient will swallow the medicament into the gastro-intestinal tract—not a desirable outcome. This loss of medicament may lead to reduced efficacy in the treatment.
Based on the above, new oral appliances are needed that improve delivery of the medicament to the target site. Oral appliances that can be easily manufactured, are preloaded and pre-dosed with medicaments, which reduce unwanted leakage, that are easy and comfortable for the patient and are not limited to the confines of home are also needed.